Orientation insensitive UHF RFID Tag Antenna With Polarization Diversity Using Characteristic Mode Analysis

This paper presents a UHF RFID tag antenna design with polarization diversity using characteristic mode analysis. The proposed tag antenna consists of two meander dipole-like structure and shorting stubs. By analyzing characteristic modes, the diagonal slots are created to scale down the resonating modes. Since the modes are depicting inductive behavior in the frequency band from 902 MHz to 928 MHz, therefore, the small capacitive slots are created to achieve mode resonance in the required RFID band. Moreover, the proposed tag design is low-cost due to the absence of vias and provide a bandwidth of more than 40 MHz with a 3D orientation insensitive read range pattern. Furthermore, the proposed tag design is able to provide a read range of 7.5 m and 4 m on a metal plate and low permittivity dielectric materials